Electrosurgical instruments are well known and widely used in the medical, dental, and veterinarian fields. They offer the capability of precision cutting with electrosurgical currents in the megacycle range using a handpiece with needle, ball, or loop electrodes in a main monopolar operating mode, or convenient coagulation (hemostasis) using a forceps in a main bipolar operating mode. Ellman International, Inc. makes available an electrosurgical instrument which provides on its front panel connectors for receiving the plug of a monopolar handpiece and a ground or indifferent plate, as well as connectors for receiving the plug of a bipolar forceps.
In a common surgical setting, a surgeon may first use the monopolar handpiece to perform a desired cutting procedure and then desire to use the bipolar forceps for coagulation of blood vessels because of its unique ability to coagulate in a fluid field. This creates problems in maintaining the requisite sterile field while still allowing the surgeon to unplug and plug in different devices from or to the instrument. One possible solution is described in U.S. Pat. No. 5,562,503, whose contents are herein incorporated by reference. In the solution proposed in this patent, an adaptor apparatus is provided and configured to plug directly into the connectors on the electrosurgical instrument, and provided with connector means for receiving mating connectors of both the monopolar handpiece and the bipolar forceps. Switch means are provided on the adaptor apparatus for allowing the surgeon to easily switch over from the monopolar to the bipolar mode by simply throwing the switch while maintaining a sterile field. However, the instrument described in this patent uses a single low frequency for the operating modes when using either a monopolar handpiece or a bipolar handpiece with the latter receiving only coagulation currents. This is not always optimum for both cutting and hemostasis. Moreover, many procedures are optimized when employing radio-frequency (RF) electrosurgical currents in the 4 MHz range, which thus requires an instrument which provides 4 MHz energy for delicate, precise and quick-healing cutting procedures, but with low leakage currents.
Moreover, under certain circumstances, it has sometimes been found that low frequency monopolar electrosurgery can cause sparking, current spread, and excessive thermal damage in the tissue because of the excessive generation of heat. Especially, this can result in deleterious effects to the tissue in proximity to the operative site in working around metal objects such as orthopedic implants, surgical screws, craniofacial metal plates and recently dental implants, thus creating the potential for electrical shock, osteoradionecrosis, and subsequent rejection of the metal implant. High frequency (3.8 to 4 MHz) energy has been proven to greatly reduce the sparking and deleterious effects of typical low frequency electrosurgical devices.
Our prior U.S. Pat. No. 5,954,686, whose contents are incorporated herein by reference, describes a novel electrosurgical instrument that provides RF energy in the 4 MHz range for the monopolar mode but a lower frequency for the bipolar mode in order to realize satisfactory hemostasis functionality. Moreover, as with the earlier instruments, only hemostasis electrosurgical currents are available in the bipolar mode. While the use of bipolar electrosurgery that employ bipolar handpieces with coaxial electrodes or parallel needles or balls for localizing the electrosurgical currents between the electrodes can reduce the deleterious effects described above, to the best of our knowledge, all bipolar electrosurgery designed for cutting operate at frequencies below 1 MHz and are not able to smoothly and precisely cut soft tissue.
To the best of our knowledge, there is no commercially-available instrument that provides high output radio-frequency (RF) energy for delicate, precise, and quick-healing cutting procedures with low leakage currents that provides multiple sub-modes of RF energy for both a monopolar handpiece and a bipolar handpiece.